Field of the Invention
The present invention relates to a rotation detection device to be used in rotation angle detection and rotational speed detection in various types of apparatuses, and relates to a rotation detection device-equipped bearing unit having the rotation detection device incorporated therein.
Description of Related Art
As conventional examples of this type of rotation detection device, there have been presented speed detectors that have a function of correcting a duty ratio or a phase shift in an output signal of an encoder by use of a correction amount stored in advance (Patent Documents 1 and 2, for example).
As another conventional example, there has also been presented a rotation detection device that outputs a pulse obtained by interpolating a reference signal of an encoder and that includes correction unit for correcting an error included in an interpolated output by use of identification information of the interpolation pulse (Patent Document 3, for example). FIG. 16 is a graph showing the comparison between the pulse period of the interpolation pulse obtained through error correction and the pulse period before the correction is performed.